Detector for locating imperfections in knitted fabrics



Sept. 16, 1947. G. E. HE NNINGV 2,427,406

DETECTOR FOR LOCATING IMPERFECTIONS IN KNITTED FABRICS Filed April 14,1945 2 SheetEs-Sheet 1 //v VENTOR 6. E. HENN/NG ATTORAEY p cs. E.HEINNING 2,427,406

DETECTOR FOR LOCATING IMPERFEGTIONS IN KNITTED FABRICS Filed April 14,1945v 2 She ts-Sheet z 22 '22 23/ 1 2a 28 I MIim w, 27 23 f i\ W '26 w26 v \2 g 4/ 43 Q 1% FIG. 5

A TTORNE V Patented Sept. 16 1947 UNITED STATES PATENT OFFICE DETECTORFOR LOCATING IMPERFEC- TIONS IN KNITTED FABRICS Application April 14,1945, Serial N 0. 588,364

12 Claims. 1

This invention relates to detectors for locatin imperfections in knittedfabrics, and has for its object the provision of new and improveddetectors for this purpose.

.In the operation of known machines for knitting a plurality of textilestrands into a fabric upon a conductor, such a knitting machinesometimes operates imperfectly and forms an imperfect fabric upon aconductor advanced therethrough. In order to adjust or repair theknitting machine and to minimize the length of the imperfect portion ofthe fabric, the imperfect portion of the fabric should be detected assoon as possible after it is formed.

A detector forming one embodiment of the invention, which is designed tobe associated with a knitting machine, for locating-imperfections inknitted fabrics, includes an apertured member having a. plurality offingers formed thereon so as to rest on a knitted fabric on a coveredconductor passing through the apertured member after the fabric has beenknitted thereon, said fingers serving to engage imperfections in aknitted fabric as the fabric i moved therealong, whereby the aperturedmember is carried with the fabric to cause a suitable mechanism to stopthe knitting machine promptly.

A complete understanding of the invention may be obtained from thefollowing detailed description of detectors forming embodiments thereof,when read in conjunction with the appended drawing, in which Fig. 1 is afragmentary, partially sectional, side View of a knitting machine and adetector embodying the invention;

Fig. 2 is an enlarged fragmentary, vertical section of a portion of thedetector;

Fig, 3 is an enlarged fragmentary, vertical section of a portion of thedetector;

Fig. 4 is an enlarged, horizontal section taken along line 4-4 of Fig.3;

Fig. '5 is an enlarged, vertical section taken along line 55 of Fig. 3;

Fig. 6 is an enlarged, fragmentary, vertical section of a portion of adetector forming an alter native embodiment of the invention, and

Fig. '7 is an enlarged, fragmentary, vertical section taken along line'l-! of Fig, 6.

Referring now in detail to the drawing, there is shown a portion of aknitting machine Ill (Fig. 1), of the type shown in co-pendingapplication, Serial No. 551,336, filed August 26, 1944, by D. G.Scrantom for Detector and automatic stop device for textile machines.This knitting machine includes a knitting head ll having a p1urality ofknitting needles l2 for knitting a plurality of feeder threads 15 into asingle-stitch tubular fabric l6 upon an insulated tinselv conductor I!to form a fabric-covered conductor l8 as the conductor 11 is advancedthrough the knitting head. The knitting machine includes a web holder 20having a bore 2| therein through which the fabric-covered conductor I8 iadvanced from the knitting head.

A detector 23 forming one embodiment of the invention is shown in Figs.1 to 4, inclusive, and includes an actuating tube 22 having a collar 25secured thereon and designed to extend into the bore 2! of the webholder 20 with the collar 25 resting upon the web holder. A bushing 26having a shoulder 21 formed thereon (Figs. 2 and 3) is secured to areduced portion 28 of the actuating tube 22 by pins (not shown), andserves to receive and hold frictionally a pair of semicylindricalbushings 3E! and 3|, which are provided with semicylindrical bores 32and 33, respectively.

The semicylindrical bushing 30 has an elongated finger 35 projectingtherefrom and the bushing 31 has two elongated fingers 36 and 31projecting therefrom. Since the bushings 30 and 3| are made of springsteel and shanks 34 of the fingers 35, 36 and 3'! are thin, the fingersare very resilient. The fingers 35, 3E and 31, which are of equallengths, taper to points 38 and are provided with contacting surfaces39, which extend to the points 38.

The normal positions of the fingers 35, 33 and 31 are such that theelongated contacting surfaces 39 lay upon equally spaced points of acircle Whose diameter is slightly smaller than that of thefabric-covered conductonand the longitudinal axes of the contactingsurfaces are parallel when the fingers are in such positions. When thesemicylindrical bushings are positioned over the fabric-coveredconductor l8 and are assembled in the bushing 26, the fabric-coveredconductor forces the fingers slightly apart so that heel portions 40thereof engage the conductor and the points 38 are spaced slightlyoutwardly from the fabric l6, as illustrated by the point 38 when in theposition shown in full lines in Fig. 5. This prevents the points 38 (Fi4) from engaging unobjectionable deviations in the fabric It as it iscarried therepast.

The bushing 39 has a pair of notches 4! (Figs. 3 and 4) formed thereinand the bushing 3! is provided with apair of tongues 43 complementary tothe notches M. The tongues 43 are designed to fit into the notches M andprevent relative longitudinal movement between the semicylindricalbushings 3S and 3! V A compression spring 42 (Fig. 1) and an annularcollar 45 are positioned between the actuating tube 22 and a latch 43.As the knitting operation proceeds, the fabric-covered conductor I8 isadvanced upwardly, as viewed in Fig. 1, through the semicylindricalbushings 30 and Si, the actuating tube 22, the compression spring d2,the collar 45 and a slot 41 formed in the latch Q6. The latch 45 ispivotally mounted upon a bracket 58 and is provided with a notchdesigned to engage a roller 52 mounted on levers 35. The levers 55 aresecured by a bolt 56 to the bracket 55! for pivotal movement withrespect thereto and are urged in a clockwise direction, as viewed inFig. 1, by a tension spring 51 secured to a pin (iii connecting thelevers 55 and to a bracket 6 I.

The latch 36, when in the positionshown in full lines in Fig. 1, servesto engage theroller 52 and hold the roller 52 in the position shown infull lines in Fig. 1, in which position the roller 52 engages aspring-pressed button 36 of a microswitch fil The microswitch (ii isconnected by conductors W to control means (not shown) of the knittingmachine I9, which control means are identical with the control meansdisclosed in the above-mentioned application, Serial No. 551,- 336. Whenthe spring-pressed button 66 is engaged by the roller 52, themicroswitch 6? permits the knitting machine to operate, but when thebutton is not engaged by the roller 52, the microswitch serves to stopthe knitting machine through the control means.

In the operation of the detector 23, the knitting head II serves to knitthe feeder threads I5 into the tubular fabric IE, which is drawn on theconductor I"! as the fabric and the conductor I! are drawn upwardly at apredetermined rate of speed from the knitting head II, through the webholder 23. The fabric-covered conductor I3 is advanced through thesemicylindrical bushings 30 and 3|, the actuating tube 22, thecompression spring 42, the annular collar 45,, and the slot 47 and thenengages a power-driven capstan of suitable design (not shown) whichdraws the fabric-covered conductor through the knitting machine andthrough all the above-mentioned elements. At this time, the latch 16 isin a posi tion in which it holds the roller 52 in a position engagingthe spring-pressed button 36 of the microswitch 31, whereby themicroswitch 6'! permits the knitting machine Iii to operate.

When the knitting head II operates perfectly,

it knits the feeder threads I5 into the fabric I3, which includes thinportions II (Figs. 2 and 3) alternating with ridge portions I2 formed ofthe interlocking portions of the feeder threads. The thin portions Itand ridge portions '82 extend along the fabric I3 in parallelrelationships with respect to each other and with respect to thelongitudinal axis of the conductor IT. The fingers 35, 36 and 3'; arespaced around the fabric It in such positions that the contactingsurfaces 39 thereof slidably engage the thin portions ii of the fabricit between the ridge portions 12 with the points 38 on the fingersspaced slightly outwardly from the fabric.

When one of the needles breaks, which sometimes occurs, the fabric I5 isformed imperfectly and wavy ridge portions 75 (Fig. 3) and humps 19(Fig. 5) are formed in the fabric. The points 38 engage the wavy ridgeportions 75 or the humps "I9 as the fabric-covered conductor I8 isadvanced upwardly, and are carried upwardly thereby, whereupon thebushings 33 and SI, the actuating tube 22, the compression spring 42,and the collar G5 are drawn upwardly with the fabric I6. This causes thelatch 33 to be moved to the position shown in dotted lines in Fig. l, inwhich position the notch in the latch iii is out of engagement with theroller 52 and the roller 52 is moved away from the spring-pressed button36 by the levers 55 and the tension spring 51. When the roller 52 ismoved away from the springpressed button 66, the microswitch til causesthe knitting machine if! to be stopped.

An operator then adjusts or repairs the knitting machine It and resetsthe latch 36 and the micros-witch 61, after disengaging the fingers 35,35 and 3? from the fabric I6 and sliding the actuating tube 22, thecompression spring 42, the collar t5 and the bushings 3i! and SIdownwardly upon the fabric I 6 to the positions in which they are shownin Fig. 1. The knitting machine Ill then may be restarted and, as longas the fabric It has no imperfections therein, can be operated.

Sometimes the needles I2 (Fig. 1) operate imperfectly in such a mannerthat a helical ridge portion l8 (Fig. 2) is formed in the fabric It.When this occurs the helical ridge portion T8 is advanced to one of thepoints 38 on the fingers 35, 33 and 37, that point engages the helicalridge portion and the operation of the knitting machine it is stopped inthe same manner as that described hereinabove.

The fingers 35, 36 and 31 of the bushings 30 and 3| serve to ride on thethin portions II of the fabric I6 without positively engaging the fabricIt as long as no imperfections occur in the fabric It. The compressionspring 42, and the taperedness and the resiliency of the fingers 35, 3Band 3'! prevent the actuation of the latch 43 and stopping of themachine by slight variations in the fabric-covered conductor I8. Also,the bushings 30 and 3| may rotate in the bushing 26, which rotationpermits the fingers 35, 33 and 31 to float between the ridge portions 12of the fabric I6. However, when imperfections such as the wavy ridgeportions I5 (Fig. 3) and humps I9 (Fig. 5) or the helical ridge portion18 (Fig. 2) are formed in the fabric I6 and are advanced to the points38 of the fingers, the points engage the wavy ridge portions, the humpsI9 or the helical ridge portion and cause the knitting machine to stop.Thus, the knitting machine In is stopped before long lengths ofimperfect fabric are formed and the knitting machine can be put intooperative condition without the waste of large quantities of fabricknitted thereby and the expense of repairing or replacing long lengthsof fabric.

A detector I23 forming an alternative embodiment of the invention isdisclosed in Figs. 6 and 7. This detector includes a bushing I26, whichis identical with the bushing 26 and which is secured to the lower endof a compression spring I42. The bushing I26 serves to frictionally holdtherein semicylindrical bushings I30 and I3! of spring steel, which areprovided with semicylindrical bores I32 and I33, respectively. Thebushing 1,353 is provided with a finger I35, and the bushing I3! isprovided with fingers I36 and I31.

The fingers I35, I33 and I3? taper to points I38 and are provided withelongated contacting surfaces I39. The fingers I35, I36 and I3! are allof different lengths and have thin shanks I34. The prong is longer thaneither of the prongs I36 and I31 and has an elongated contactin"shoulder I29 forming a continuation of the contacting surface I39thereof, and the contacting shoulder contacts ridge portions such asstraight ridge portions I12 of a fabric II 6 to hold the bushings I30and I3I in equilibriumon the fabric, as the fabric, which covers aninsulated conductor M1 to form a fabric-covered conductor H8, isadvanced through the bushings. Ex- 'cept for their difierences inlengths and-the shoulder I29, the fingers I35, I36 and I31 are identicalwith the fingers 35, 36 and 31. A pair of tongues illustrated by atongue I43 (Fig. '1) are provided on the semicylindrical bushing I30 andare designed to project into notches, such as the notch I4I, formed inthe semicylindrical bushing I3I to hold the bushings I30 and I3I againstlongitudinal movement therebetween.

The bushing I26 serves to hold the semicylindrical bushings I30 and I3Iin positions around the fabric II6 knitted upon the conductor II1 by aknitting head (not shown) identical with the knitting head II, with thefingers I35, I36 and I31 thereof pressed against the fabric H6. Thefingers I35, I36 and I31 are of such difierent lengths that, when thesemicylindrical bushings I30 and I3I are assembled, the points I38 atthe ends thereof lay upon points of a helix, which helix is the same asthat along which a helical ridge portion I18 of the fabric H6 issometimes formed by imperfect operation of the knitting machine withwhich the bushings I30 and I 3I are associated. Normally this knittingmachine forms straight thin portions I1I of the fabric II 6 alternatingwith the straight ridge portions I12 thereof, and heel portions I40 ofthe contacting surfaces I39 ride on the thin portions I1I between thestraight ridge portions I12. When the knitting machine knits continuousimperfections into the fabric II6, such as the continuous helical ridgeportion I18 of loosely knitted loops, all of the points I38 positivelyand simultaneously engage the helical ridge portion ,I18 as'it isadvanced thereto and are drawn upupon the knitting machine can beadjusted to operate correctly. The points I38 also serve to engageimperfections such as the wavy ridge portions (Fig. 3) and humps 19(Fig. 5), when such imperfections occur, and stop the knitting machineassociated therewith. The resiliency imparted to the fingers I35, I36and I 31 by the thin shanks I34 causes the heel portions I40 of thecontacting surfaces I39 to remain at all times in close contact with thefabric IIB, while the taperedness of the fingers I35, I36 and I31 andthe outwardly spaced points I 38 together with the action of thecompression spring I42 permit unobjectionable deviations in thefabric-covered conductor II8 to be advanced therepast witharound aconductor to form a covered conductor which is advanced therethrough, abushing having a plurality of resilient fingers projecting therefrom inpositions spaced around a covered conductor as it is advanced throughthe bushing, said fingers tapering to points and also being providedwith contacting surfaces and being arranged so that the contactingsurfaces normally touch a circle whose diameter is less than that of thecovered conductor, whereby the fingers are spread outwardly when inengagement with the covered conductor and the points thereof do notengage'perfect portions of the cover but do engage imperfect portionsthereof.

2. In a detector for use with a knitting machin including a knittinghead fo knitting a plurality of strands into a fabric upon an insulatedconductor to form a fabric-covered conductor as the insulated conductoris advanced therethrough in a predetermined direction, a detector forlocating imperfections in a fabric knitted on an insulated conductor bythe knitting head, which comprises a tubular member having a pluralityof resilient fingers projecting therefrom in parallel relationship,means for positioning the tubular member around a fabric-coveredconductor in a position in which the resilient fingers rest on thefabric of the conductor at equally spaced points thereon and point in adirection opposite to that in which the fabric-covered conductor isadvanced through the knitting head.

3. For use with a knitting machine including a knitting head forknitting a plurality of strands into a tubular covering upon aninsulated conductor to form a fabric-covered conductor as the insulatedconductor is advanced therethro gh, means for stopping the knittingmachine, and a pivotally mounted lever for actuating the stopping means,a detector locating imperfections in a tubular covering of afabric-covered conductor formed by the knitting machine, which comprisesa split bushing having a plurality of fingers pro vided with taperedpoints and positioned over the tubular covering, said fingers being ofsuch different lengths that the tapered points thereof lay on a helixand being designed to slide upon the tubular covering as thefabric-covered conductor is advanced relative to the bushing with thetapered points spaced slightly from perfect portions of the tubularcoverin but laying in the path of imperfections thereof, and a springfor connecting the split bushing to the lever, whereby the lever ispivoted by the bushing when one of the fingers engages an imperfectionin the fabric and the knitting machine is stopped.

4. For use in a knitting machine including a knitting head for knittinga plurality of strands into single-stitch fabric around a conductor toform a fabric-covered conductor as the conductor is advancedtherethrough, said fabric including raised ridge portions extendingalong the conductor in parallel relationships therewith and thinportions extending along the conductor in parallel relationshipstherewith, and means for stopping the knitting machine, a detector for10- cating imperfections in the fabric of a fabricccvered conductorformed by the knitting machine, which comprises a bushing having aplurality of tapered fingers projecting therefrom and positioned aroundthe fabric, said fingers being spaced around the fabric so as to restupon the thin portions of the fabric, and means for connecting thebushing operatively to the stopping means, whereby the bushin actuatesthe stopping means when one of the fingers engages an imperfection inthe fabric.

5, For use in a knitting machine including a knitting head for knittingover a conductor as the conductor is advanced therethrough a pluralityof strands into single-stitch fabric to form a fabric-covered conductor,said fabric including -ridge portions extending along the conductor inposite to that in which the fabric is advanced and to lay on points of ahelix, and a compression spring for connecting the bushing operativelyto the stopping means, whereby the bushing actuates the stopping meanswhen one of the points of the fingers engages an imperfection in thefabric.

6. For use in a knitting machine including a knitting head for knittingupon a conductor as the conductor is advanced therethrough a pluralityof strands into a fabric to form a fabriccovered conductor and means forstopping the knitting machine, a detector for locating imperfection inthe fabric of a fabric-covered conductor formed by the knitting machine,which comprises a plurality of resilient fingers having surfaces formedthereon for engaging slidably the fabric, said fabric-engaging surfacestapering to points and laying normally upon a circle whose diameter isless than that of the fabricoovered conductor, and means serving tomount the fingers in positions in which the fingers are spaced aroundthe fabric with the fabric-engaging surfaces thereof in contact with thefabric in floating relationships therewith and to connect operativelythe fingers and the stopping means, whereby the stopping means isactuated when one of the points of th fingers engages an imperfection inthe fabric.

'7. For use in a knitting machine including a knitting head for knittinga plurality of strands upon a conductor as the conductor is advancedtherethrough to form a fabric-covered conductor and means for stoppingknitting machine, a detector for locating imperfections in the fabric ofa fabric-covered conductor formed by the knitting machine, whichcomprises a tubular member having a plurality of resilient fingers whichare of different lengths and which have surfaces formed thereon forengaging slidably a fabric knitted upon a conductor by the knitting headand also provided with points spaced slightly from the fabric, saidfingers projecting from the tubular member in positions in which theyare spaced around the fabric with the points thereof being positioned onpoints of a helix, and a compression spring for connecting the tubularmember and the stopping means, whereby the stopping means is actuatedwhen one of the points of the fingers engages an imperfection in thefabric, the longest of said fingers also being provided with a shoulderfor engaging the fabric to hold the tubular member in equilibrium uponthe fabric.

8. For use in a knitting machine including a knitting head for knittingupon a conductor as the conductor is advanced therethrough a fabric toform a fabric-covered conductor and means for stopping .the knittingmachine, a detector for locating imperfections in a fabric of afabriccovered conductor formed by the knitting head, which comprises atubular member for surrounding the fabric-covered conductor as thefabriccovered conductor is advanced from the knitting head, a pluralityof resilient fingers projecting from the tubular member in directionsparallel with the axis of the fabric-covered conductor, said fingershaving points formed at the extremities thereof and also being providedwith fabric-engaging surfaces adjacent to the points serving to hold thepoints away from fabric normally but to permit the points to engageimperfections in the fabric to cause the tubular member to be carriedalong with the advancing fabric-covered conductor, and means operativelyassociated with the tubular member for actuating the stopping means whenthe tubular member has been advanced a predetermined distance.

9. For use in a knitting machine including a knitting head for knittingupon a conductor as the conductor is advanced therethrough a fabric toform a fabric-covered conductor and means for stopping the knittingmachine, a detector for locating imperfections in a fabric knitted bythe knitting head upon a conductor, which comprises a split tubularmember, a bushing for mounting the split tubular member rotatablytherein in a position in which it surrounds the fabric-covered conductoras it is advanced from the knitting head, a plurality of resilientfingers having points at the extremities thereof projecting from thetubular member in directions parallel with the axis of thefabric-covered conductor, said fingers also being provided withfabric-engaging surfaces extending to the points and being sprungoutwardly by the fabric-covered conductor so that the points formed atthe extremities thereof do not engage perfect portions of the fabric butengage imperfections in the fabric and cause the tubular member and thebushing to be carried along with the advancing fabric-covered conductor,and a compression spring connected to the bushing for actuating thestopping means when the tubular member and the bushing have been carrieda predetermined distance.

10. For use in a knitting machine including a knitting head for knittingupon a conductor as the conductor is advanced therethrough a fabrichaving ridge portions and thin portions extending along the fabricparallel with the conductor to form a fabric-covered conductor and amicroswitch for stopping the knitting machine when actuated, a detectorfor detecting imperfections in such a, fabric, which comprises aplurality of elongated fingers, a bushing for mounting the fingers in aring-like fashion around a fabriccovered conductor in positions in whichthe fingers rest on the thin portions of the fabric,

whereby smooth portions of the fabric slide past the fingers butroughened portions of the fabric are engaged by the fingers and move thefingers and the bushing therewith as the fabric-covered conductor isadvanced, and a spring for connecting the bushing operatively with themicroswitch to actuate the microswitch when the fingers engage aroughened portion of the fabric.

11. For use in a knitting machine including a knitting head having aplurality of needles for knitting upon a conductor as the conductor isadvanced therethrough a plurality of strands into a fabric to form afabric-covered conductor, said fabric having ridge portions extendingtherealong in positions parallel with the conductor and thin portionspositioned between the ridge portions, means for stopping the knittingmachine when actuated, a detector for locating imperfections in thefabric, which comprises a split tubular member having pointed resilientfingers projecting therefrom, a bushing for mounting the split tubularmember rotatably therein, and a compression spring serving to connectthe bushing operatively to the stopping means and to mount the bushingand the split tubular member in positions in which they surround thefabric-covered conductor, said fingers having surfaces formed thereonfor pressing against the thin portions of the fabric with the points ofthe fingers spaced outwardly from the fabric-covered conductor, saidsurfaces being shorter than the distances between humpy portions of thefabric occurring when one of the needles breaks, whereby the points ofthe fingers engage the humps in the fabric as the fabric-coveredconductor is advanced therepast and cause the compression spring toactuate the stopping means when the fingers have been carried apredetermined distance with the fabric-covered conductor.

12. For use in a knitting machine including a knitting head for knittinga plurality of strands into a fabric, means for advancing fabric formedby the knitting head in a predetermined direc- 10 tion from the knittinghead as the fabric is formed and means for stopping the knittingmachine, a detector for locating imperfections in the fabric comprisinga plurality of elongated resilient fingers having points and heelsformed thereon, means for holding the fingers in parallel positions inwhich the heels on the fingers are pressed against the fabric to holdthe points on the fingers slightly away from perfect portions of thefabric but in the path of any imperfection occurring in the fabric,means for mounting the fingers for lateral floating movement with thefabric, and means for connecting operatively the fingers and the meansfor stopping the knitting machine so that the latter means is actuatedwhen the point on one of the fingers engages an imperfection in thefabric.

GEORGE E. HENNING.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,190,169 Bardsley Feb. 13, 19402,368,686 Sperzel Feb. 6, 1945

